Populate

A newly created bunch has its all particle coordinates initialized to 0.0.

• User may choose to populate the particle coordinates by directly accessing the particle data as shown in previous section.

particles = bunch.get_particles_numpy()

particles[:, 0] = 0.01
particles[:, 1:6] = 0.0

# sync to device
bunch.checkin_particles()

• Synergia also provides a range of bunch populate methods to initialize the particle to certain distributions. For example, the following one populate a bunch with given means and covariances,

# mean and covariance matrix. The covariances matrix is 6x6
bunch_means = np.zero(6, dtype='d')
bunch_covariances = np.array([[...], [...], [...], [...], [...], [...]])

# use the provided random number generator with an integer value of seed
dist = synergia.foundation.PCG_random_distribution(seed)

# populate a Gaussian bunch
synergia.bunch.populate_6d(dist, bunch, bunch_meas, bunch_covariances)

• A bunch can also be initialized from reading a generated particle file. The size of the bunch will be adjusted to fit all particles from the particle file.

bunch.read_file("turn_particles_0000.h5")